Slotted convergence cup electrode for color television tube with flanged rim snubber springs,and having flanged magnetic pole pieces therein



Apr1l29, 1969 O J. H. JOHNSON 3, O

SLOTTED CONVERGENCE CUP ELECTRODE FOR COLOR TELEVISION TUBE 7 WITH FLANGED RIM SNUBBER SPRINGS, AND HAVING FLANGED MAGNETIC POLE PIECES THEREIN Filed April 26, 1967 INVEN'T OR Jz'yfi. Jdlzjwb,

BY WQM ATTORNEY United States Patent ()fice 3,441,769 Patented Apr. 29, 1969 US. Cl. 313-84 4 Claims ABSTRACT OF THE DISCLOSURE Uninterrupted flanges are provided to extend outwardly around the top edge of a generally cylindrical thin walled non-magnetic convergence electrode body having a closed bottom, thus being shaped as a cup. Internally mounted Y-shaped shield inserts of magnetic material are aflixed to the inner wall of the body, so that only six slots are needed for insertion of magnetic pole pieces, all spaced to pass through the walls between the top edge and closed bottom. Snubber springs are either affixed to the inside walls of the cup electrode or are clfset to bypass the top edge flanges when aflixed to the outside walls of the cup electrode.

This invention relates to electrodes for controlling a beam within a cathode ray tube, and more particularly, it relates to a convergence cup electrode for three beam color television tubes.

Basically, this convergence cup electrode is a cup-like electrode of generally cylindrical shape of a thin-walled non-magnetic metal. Inside the cup is a generally Y-shaped magnetic shield dividing the interior of the cylinder into three substantially equal compartments. A set of two magnetic pole pieces protrude from the outside through two slots in each compartment to straddle an aperture in the closed cup bottom which passes an electron beam. Snubber springs are aflixed to extend generally outwardly from the electrode to press against the inside surface of the glass neck of the cathode ray tube for centering the gun therein. The pole pieces have flanges adjacent the outer walls of the electrode and near the glass neck of the tube to communicate with convergence magnets located outside the tube envelope.

In constructing this convergence cup assembly, great difficulty has been encountered in holding the roundness of the convergence cup cylinder. It has been found that in punching six pole piece slots and three shield slots through the electrode walls, the cylindrical shape may be distorted out of tolerance.

Thus, this invention has a primary objective the provision of a new convergence cup assembly which can be manufactured within desired roundness tolerances.

A further object of the invention is to provide improved centering means for a convergence cup electrode.

It has been discovered in accordance with this invention that the convergence cup may be formed from a deep drawn cup having an outwardly flanged upper rim that is mechanically more rigid. To avoid some of the punched slots which tend most to distort the roundness at the upper rim, the Y-shaped shield is aifixed to the inner walls of the cylinder body by flanges abutting the walls. The snubber springs are either bypassed around the flanged edge if mounted on the outside walls, or are mounted on the inside walls to avoid interruption to the flanges and to preserve the mechanical strength and roundness of the electrode body. The bypassed snubber springs are formed with an additional bearing surface to ride on the inner tube envelope surface to provide an improved centering mount for the convergence electrode therein.

The foregoing features of the invention together with further advantages and objects will be made evident from the following detailed description referring to a specific embodiment illustrated in the accompanying drawings, wherein:

FIGURE 1 is a top view of a convergence cup electrode constructed in accordance with this invention;

FIGURE 2 is a side view of the convergence cup;

FIGURE 3 is a fragmental section side view showing an alternative snubber spring mount afforded in accordance with the invention; and

FIGURE 4 is a fragmental section view of a snubber spring assembly.

As seen from the drawing, the convergence cup may be a deep drawn cylinder having a closed bottom 10 with rounded corners 11. This cup has thin walls 12 of non-magnetic metal with the upper rim 14 flanged outwardly. Slots 15, 16 are punched through the cup walls in six places defining three compartments 18, 19, 20. To prevent from disturbing the roundness of the cylinder body, the slots are spaced from both the top flanged edge 14 and the bottom 10 of the cup by separator spaces 21, 23, respectively.

Two pole pieces 30, 31 extend through slots 15, 16 into each compartment 18, 19, 20 to straddle apertures 32, 33, 34 which permit three electron beams to pass through the convergence electrode. The flanges on the pole pieces 30, 31 abut the outer walls of the cylinder to extend near the inner wall of the glass neck of the tube 35 about which a convergence magnet array is placed to communicate with the pole pieces.

In addition, at least three snubber springs 40 extend generally outwardly from the electrode cup to engage the inner walls of the tube neck 35. These may be mounted on the outside walls of the cup electrode as shown in FIG- URE 2, but in this case an olfset 41 is provided to prevent interruption of the flanged rim 14. Alternatively, the snubber springs may have straight shanks 42 atfixed to the inside walls of the cylinder as shown by snubber 40 in FIGURE 3.

As seen from the revised offset snubber 41' of FIG- URE 4 having a generally semi-circular protrusion, an additional bearing surface is provided to rest against the inner surface of the envelope or tube neck 35, thereby resulting in better centering of the convergence cup electrode 10 therein.

It has been found that this construction facilitates the holding of roundness of convergence cup assemblies during manufacture and results in an improved electrode with fewer rejects, more precise operation, and better centering characteristics.

What is claimed is:

1. A convergence cup assembly for mounting in the neck portion of a three-beam color television tube comprising in combination, a hollow cylindrical thin-walled electrode body of non-magnetic material having a closed bottom and a top edge outwardly flanged over to form a lip extending outwardly from the cylinder, a generally Y-shaped shield insert of magnetic material dividing the interior of the cylinder into three substantially equal compartments, said cup having aperture means disposed in the walls of said cylinder in each compartment for receiving two additional elements spaced apart and spaced from said flanged top edge and said closed bottom, a pair of magnetic pole pieces extending into each compartment at each of said aperture means and afiixed to said body by a flange conforming to the outer wall of said cylindrical body, and three apertures defined in said closed bottom for passing respective electron beams through each compartment between said pair of magnetic pole pieces, a set of at least three snubber springs aflixed to said assembly and extending past the top edge of said body and generally outwardly from said cylinder, wherein the set of snubber springs includes at least one which is afiixed to the outer surface of said cylindrical body and includes an olfset portion bypassing the outwardly flanged top edge of said body.

2. A convergence cup assembly for mounting in the neck portion of a three-beam color television tube comprising in combination, a hollow cylindrical thin-walled electrode body of non-magnetic material having a closed bottom and a top edge outwardly flanged over to form a lip extending outwardly from the cylinder, a generally Y-shaped shield insert of magnetic material dividing the interior of the cylinder into three substantially equal compartments, said cup having aperture means disposed in the walls of said cylinder in each compartment for receiving two additional elements spaced apart and spaced from said flanged top edge and said closed bottom, a pair of magnetic pole pieces extending into each compartment at each of said aperture means and affixed to said body by a flange conforming to the outer wall of said cylindrical body, and three apertures defined in said closed bottom for passing respective electron beams through each compartment between said pair of magnetic pole pieces, a set of at least three snubber springs afiixed to said assembly and extending past the top edge of said body and generally outwardly from said cylinder, wherein one snubber spring is afi'ixed to an interior wall of the cylindrical body at a location within each of the compartments.

3. An assembly as defined in claim 1, wherein the tube has an envelope surrounding the snubber spring, and the offset portion includes a bearing surface resting against the inner surface of the tube.

4. An assembly as defined in claim 3, wherein the snubber spring has two generally semi-circular protrusions resting against the inner surface of the neck of the tube envelope.

References Cited UNITED STATES PATENTS 2,991,381 7/1961 Hughes 3l370 X 3,011,090 11/1961 Moodey 313-70 X 3,128,407 4/1964 Mattson 313-82 3,322,990 5/ 1967 Fiore 3 l3-70 JAMES W. LAWRENCE, Primary Examiner.

V. LAFRANCHI, Assistant Examiner.

US. Cl. X.R. 

